Caliper measurement of thin films and functional coatings applied to the thin films is important to the industry producing these products. Typically, the measurements involve removal of samples or representative pieces of the product from a production process. These systems include use of fluorescence, light absorbance, and physical measurement techniques. However, these techniques are limited to a single fluorescence or absorbance probe in a single functional coating or thin film. Many thin film products now have multiple functional coatings, often applied simultaneously. However, there is no method or apparatus for evaluating multiple functional coatings in an on-line manufacturing process where that manufacturing process is simultaneously applying multiple functional coatings onto a thin film.